This invention relates to processing agents for synthetic fibers, aqueous liquids of these processing agents, methods of processing synthetic fibers by using such aqueous liquids, and synthetic fibers obtained by methods using such aqueous liquids.
It has been known in the production and fabrication processes of polyester and polyamide synthetic fibers to apply a processing agent for synthetic fibers such as spinning oil either as an aqueous system or as a non-aqueous system. If a processing agent for synthetic fibers is applied as a non-aqueous system, such as in the condition of being diluted with an organic solvent (as described, for example, in Japanese Patent Publications Tokkai 57-199868 and 6-57541), however, problems frequently arise regarding costs, disaster prevention and safety.
If a processing agent for synthetic fibers is applied as a low-concentration aqueous system, such as in the condition of an about 10% emulsion (as described, for example, in Japanese Patent Publication Tokkai 7-216733), on the other hand, the problems regarding costs, disaster prevention and safety can be eliminated but problems frequently arise regarding yarn quality and dyeing property.
It has also been proposed to supply a processing agent for synthetic fibers as an emulsion of a higher concentration such as about 30% or even about 50% (as described, for example, in Japanese Patent Publication Tokkai 6-280160), but the emulsion of the processing agent in such a case would tend to gelate, making it impossible to attach the processing agent to yarns uniformly such that the problem arises as a result that the requested high levels of spinning property, yarn quality and dyeing property cannot simultaneously be attained.